Role of
water in the body - Vehicle the elements circulating in the blood: globules,
dissolved elements (sodium, calcium, oxygen ...), - Vehicle the elements of
certain secretions: tears, digestive juice ..., - Contributes to the regulation
of the body temperature through perspiration, - Allows the elimination of the
soluble waste in the urine (waste drainage) II) PROPERTIES OF WATER. 1) Melting
point and boiling water A body can take 3 states: Solid, liquid or gaseous.
Every passage from one state to another is called a change of state. The heat
produces a vibratory motion which makes the cohesion of the molecules less
strong and which allows the molecules to roll freely on each other. SOLID GAS
LIQUID Solidification Fusion Liquefaction or condensation in the liquid state
Condensation in the solid state Sublimation Vaporization Melting: This is the
transition from solid to liquid. This change of state is obtained by bringing heat
to the body that one wishes to change state. For water, we say that the ice
melts. Spraying: This is the transition from the liquid state to the gaseous
state. This change of state is obtained by bringing heat to the body that one
wishes to change state. For water, we say it boils. Condensation: This is the
transition from the gaseous state to the liquid state. To achieve this change
of state, the body must yield heat. Solidification: This is the transition from
the liquid state to the solid state. To achieve this change of state, the body
must yield heat. It will be said for the water that it freezes. Sublimation:
This is the direct passage from the solid state to the gaseous state without
going through the liquid state. To achieve this change of state, the body must
take heat from the environment. this change of state is obtained under
particular pressure and temperature conditions. The best-known body that
achieves this change of state is naphthalene (anti-mothball). Temperature is
therefore a measure of the degree of agitation of the material. Boiling water:
100 ° C Melting ice: 0 ° C
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